This invention relates generally to coating tubing bores; and more particularly concerns coating tubing bores of varying diameters.
U.S. Pat. No. 3,322,559 (incorporated herein by reference) discloses a method of coating the interiors of constant diameter tubes, at and near the ends thereof. There is need for apparatus and method to coating tubing of variable diameters, as for example condenser tubes having protective insert tubes terminating therein, the insert tubes having inner tubes terminating therein, the insert tubes having inner diameters less than the inner diameters of the condenser tubes. Such insert sleeves (or tubes) are used to cover damaged or cavitated areas of condenser, the critical area being the transition between the two diameters of the sleeve and condenser tube, whereby coating same is desirable. Such coatings act to prolong the lives of the condenser tubes and insert sleeves, and such coatings prolong the uses of the tubes. In this regard, the cost of changing condenser tubes in electric generating plants is extremely high, so that extending tube useful life is very desirable.